People are increasingly relying upon electronic devices for a variety of different tasks. Accordingly, there is an increasing number of ways in which a user can interact with a device to perform these tasks. In some cases, an electronic device might record audio or video information corresponding to a user of the device, and might perform processes such as image recognition or voice analysis. In many of these cases, a device would have to capture and analyze information corresponding to a large area or region around the device. If the device is interested in information from only a portion of this area, the device can waste significant resources capturing and/or analyzing information over the entire area. Such waste can be particularly problematic for portable devices that run on battery power, as the extra resource usage can unnecessarily drain the battery and/or slow functionality of the device.